Fuel additive composition

ABSTRACT

A composition of additives for fuel including: one or more copolymer(s) including:—at least one unit of the following formula (I): wherein R1 is selected from hydrogen and methyl group, R′2 is selected from C1 to C34 hydrocarbon-based chains, an aromatic ring, an aralkyl containing at least one aromatic ring and at least one C1-C34 alkyl group, and—at least one unit of following formula (II): wherein R1 is selected from hydrogen and methyl group, Z is selected from the oxygen atom and —NR′— group with R′ being selected from a hydrogen atom and C1 to C12 hydrocarbon-based chains, G includes a C1 to C34 hydrocarbon-based chain substituted with at least one quaternary ammonium group and optionally one or more hydroxyl groups, group G also possibly containing one or more nitrogen and/or oxygen atoms and/or carbonyl groups 25 at least one compound selected from succinimides substituted with a hydrocarbon-based chain.

The present invention relates to an additive composition for the liquid fuel of an internal combustion engine.

PRIOR ART

Liquid fuels for internal combustion engines contain components that can degrade during the functioning of the engine. The problem of deposits in the internal parts of combustion engines is well known to motorists. It has been shown that the formation of these deposits has consequences on the performance of the engine and notably has a negative impact on consumption and particle emissions. Progress in the technology of fuel additives has made it possible to confront this problem. “Detergent” additives used in fuels have already been proposed to keep the engine clean by limiting deposits (“keep-clean” effect) or by reducing the deposits already present in the internal parts of the combustion engine (“clean-up” effect). Mention may be made, for example, of U.S. Pat. No. 4,171,959 which describes a detergent additive for gasoline fuel containing a quaternary ammonium function. WO 2006/135881 describes a detergent additive containing a quaternary ammonium salt used for reducing or cleaning deposits, notably on the inlet valves. However, engine technology is in constant evolution and the stipulations for fuels must evolve to keep pace with these technological advances of combustion engines. In particular, the novel gasoline or diesel direct-injection systems expose the injectors to more severe pressure and temperature conditions, which promotes the formation of deposits. In addition, these novel injection systems have more complex geometries to optimize the spraying, notably, from more numerous holes having smaller diameters, but which, on the other hand, induce greater sensitivity to deposits. The presence of deposits may impair the combustion performance and notably increase pollutant emissions and particle emissions. Other consequences of the excessive presence of deposits have been reported in the literature, such as the increase in fuel consumption and driveability problems.

Preventing and reducing deposits in these novel engines are essential for optimum functioning of modern engines.

WO 2017/046526 discloses the use, as detergent additive in a liquid fuel for an internal combustion engine, of a copolymer comprising at least one block A and at least one block B. Block A is obtained from alkyl (meth)acrylate monomers. Block B is obtained from alkyl (meth)acrylate or alkyl(meth)acrylamide monomers, said alkyl group being substituted with at least one quaternary ammonium group.

Another important problem associated with liquid fuels for internal combustion engines is linked to the presence of residual water within these fuels. Due to the process used for extracting the crude oil but also because of the condensation of water which may take place during the transportation and storage thereof, fuels comprise a variable amount of water that may range from a few parts per million to several percent by mass relative to the total mass of the fuel. The presence of this residual water generally leads to the formation of stable emulsions which, being suspended within the fuel, are the cause of numerous problems that arise during the transportation and/or combustion of these fuels. For example, these emulsions may cause obstruction of the engine filters or accelerate the corrosion of the engine.

The detergent additives currently used in fuels have a tendency to stabilize the emulsions present in the fuel. Their presence is then reflected by a degradation of the demulsifying properties of the fuels, in particular of gas oils and of gasolines. In order to overcome these problems, it is common practice in the field of fuels to use demulsifying additives (or demulsifiers). These demulsifying additives then make it possible to break the water-in-fuel emulsions and to allow the separation of the water and of the fuel. As examples of demulsifying additive compositions, mention may be made of those taught by U.S. Pat. No. 4,129,508.

More recently, US 2016/0160144 proposes the use of a polyisobutenylsuccinic acid in combination with one or more detergent additives in order to improve the separation of water and fuel.

Numerous prior art documents describe the dehazing of fuels comprising water. This dehazing corresponds in reality to the stabilization of the water-in-fuel emulsion in order to obtain a fuel composition of one-phase appearance (emulsification). In contrast with demulsifying, dehazing does not allow the separation of water and fuel and therefore does not constitute a solution to the drawbacks described previously.

Consequently, there is still a need to propose an additive-mediated solution for giving fuels good detergent properties while at the same time maintaining or even improving the demulsifying of said fuel.

OBJECT OF THE INVENTION

The invention relates first to a fuel additive composition comprising:

(a) one or more copolymers comprising:

at least one unit of formula (I) below:

in which R₁′ is chosen from hydrogen and a methyl group, R′₂ is chosen from C₁ to C₃₄ hydrocarbon-based chains, an aromatic nucleus, an aralkyl comprising at least one aromatic nucleus and at least one C₁ to C₃₄ alkyl group, and

at least one unit of formula (II) below:

in which R₁ is chosen from hydrogen and a methyl group, Z is chosen from an oxygen atom and a group —NR

with R□ being chosen from a hydrogen atom and C₁ to C₁₂ hydrocarbon-based chains, G comprises a C₁ to C₃₄ hydrocarbon-based chain substituted with at least one quaternary ammonium group and optionally one or more hydroxyl groups, the group G also possibly containing one or more nitrogen and/or oxygen atoms and/or carbonyl groups, (b) at least one compound selected from succinimides substituted with a hydrocarbon-based chain.

Preferably, the group G of formula (II) is represented by one of the formulae (III) and (IV) below:

in which: X⁻ is chosen from hydroxide and halide ions and organic anions, preferably organic anions, R₂ is chosen from C₁ to C₃₄ hydrocarbon-based chains, optionally substituted with at least one hydroxyl group, it being understood that the group R₂ is connected to Z in formula (II), R₃, R₄ and R₅ are identical or different and chosen independently from C₁ to C₁₈ hydrocarbon-based chains, it being understood that the alkyl groups R₃, R₄ and R₅ may contain one or more groups chosen from: a nitrogen atom, an oxygen atom and a carbonyl group and that the groups R₃, R₄ and R₅ may be connected together in pairs to form one or more rings, R₆ and R₇ are identical or different and chosen independently from C₁ to C₁₈ hydrocarbon-based chains, it being understood that the groups R₆ and R₇ may contain one or more groups chosen from: a nitrogen atom, an oxygen atom and a carbonyl group and that the groups R₆ and R₇ may be connected together to form a ring.

More preferentially, the group G of formula (II) is represented by formula (III) in which:

X⁻ is chosen from organic anions, preferably conjugate bases of carboxylic acids,

R₂ is chosen from C₁ to C₃₄ hydrocarbon-based chains, preferably C₁ to C₁₈ alkyl groups,

R₃, R₄ and R₅ are identical or different and chosen independently from C₁ to C₁₈ hydrocarbon-based chains, optionally substituted with at least one hydroxyl group, it being understood that at least one of the groups R₃, R₄ and R₅ contains at least one hydroxyl group.

Preferably, the copolymer(s) consist exclusively of units of formula (I) and of units of formula (II).

According to a particular embodiment, the copolymer is obtained by copolymerization of at least:

one monomer (m_(a)) corresponding to formula (VII) below:

in which R₁′ and R₂′ are as defined above,

one monomer (m_(b)) chosen from those of formula (VIII) below:

in which R₁, Z and G are as defined above.

According to a preferred embodiment, the copolymer is a block copolymer.

Preferably, the block copolymer comprises at least one block A and at least one block B.

More preferentially, the block copolymer comprises:

a block A corresponding to formula (XI) below:

in which p is an integer ranging from 2 to 100, R₁′ and R′₂ are as defined above,

a block B corresponding to formula (XII) below:

in which n is an integer ranging from 2 to 40, R₁, Z and G are as defined above.

Preferably, the succinimide compound substituted with a hydrocarbon-based chain (b) is selected from polyisobutene succinimides.

Advantageously, the mass ratio between the copolymer(s) (a) and the succinimide compound (b) ranges from 5:95 to 95:5, preferably from 10:90 to 90:10.

The invention also relates to a fuel concentrate comprising a fuel additive composition as defined above and in detailed manner below, as a mixture with an organic liquid, said organic liquid being inert with respect to the copolymer(s) (a) and the succinimide compound(s) (b) and miscible with said fuel.

The invention also relates to a fuel composition comprising:

(1) a fuel derived from one or more sources chosen from the group consisting of mineral, animal, plant and synthetic sources, and (2) a fuel additive composition as described above and in detailed manner below.

Preferably, the fuel composition according to the invention comprises at least 5 ppm of copolymer(s) (a).

More preferentially, the copolymer(s) (a) are present in the composition according to the invention in an amount ranging from 1 to 1000 ppm, preferably ranging from 5 to 500 ppm, more preferentially ranging from 10 to 200 ppm and even more preferentially ranging from 20 to 100 ppm.

Preferably, the succinimide compound (b) is present in the fuel composition according to the invention in an amount ranging from 1 to 1000 ppm, preferably ranging from 5 to 500 ppm, more preferentially ranging from 10 to 200 ppm and even more preferentially ranging from 20 to 100 ppm.

Preferably, the fuel (1) is chosen from hydrocarbon-based fuels, fuels that are not essentially hydrocarbon-based, and mixtures thereof.

The invention also relates to the use of a fuel additive composition as described above, as detergent additive in a liquid fuel for internal combustion engines, said fuel additive composition being used alone or in the form of a concentrate as defined above and in detailed manner below.

According to a particular embodiment, the fuel additive composition is used in the liquid fuel for keeping clean and/or cleaning at least one of the internal parts of said internal combustion engine.

According to a particular embodiment, the fuel additive composition according to the invention is used in the liquid fuel for limiting or preventing the formation of deposits in at least one of the internal parts of said engine and/or for reducing the existing deposits in at least one of the internal parts of said internal combustion engine.

According to a particular embodiment, the fuel additive composition according to the invention is used in the liquid fuel for reducing the fuel consumption of the internal combustion engine.

According to a particular embodiment, the fuel additive composition according to the invention is used in the liquid fuel for reducing the pollutant emissions, in particular the particle emissions of the combustion engine.

Finally, the invention relates to the use of a fuel additive composition as described above for improving the separation of water and fuel when said fuel contains water, said fuel additive composition being used alone or in the form of a concentrate as defined above and in detailed manner below.

DETAILED DESCRIPTION

Other advantages and features will emerge more clearly from the description that follows. The particular embodiments of the invention are given as nonlimiting examples.

For the sake of simplicity, the following terms will be used in the rest of the description:

“alkyl (meth)acrylate” to denote an alkyl acrylate or an alkyl methacrylate (alkyl (meth)acrylate),

“alkyl(meth)acrylamide” to denote an alkylacrylamide or an alkylmethacrylamide (alkyl(meth)acrylamide),

“quaternary ammonium” to denote a quaternary ammonium salt.

For the purposes of the invention, the term “unit” means a group of atoms constituting a part of the structure of the copolymer and corresponding to a monomer employed in the synthesis of the copolymer.

The invention relates to a fuel additive composition comprising:

a) one or more copolymers comprising:

at least one unit of formula (I) below:

in which R₁′ is chosen from hydrogen and a methyl group; preferably, R₁′ is a hydrogen atom, R′₂ is chosen from C₁ to C₃₄ hydrocarbon-based chains, an aromatic nucleus, an aralkyl comprising at least one aromatic nucleus and at least one C₁ to C₃₄ alkyl group, and

at least one unit of formula (II) below:

in which R₁ is chosen from hydrogen and a methyl group, Z is chosen from an oxygen atom and a group —NR

with R□ being chosen from a hydrogen atom and C₁ to C₁₂ hydrocarbon-based chains, G comprises a C₁ to C₃₄ hydrocarbon-based chain substituted with at least one quaternary ammonium group and optionally one or more hydroxyl groups, the group G also possibly containing one or more nitrogen and/or oxygen atoms and/or carbonyl groups, and b) at least one compound selected from succinimides substituted with a hydrocarbon-based chain.

Copolymer (a)

According to a particular embodiment, the units of formula (I) and the units of formula (II) defined above represent at least 70 mol % of the copolymer (a), relative to the number of moles of units included in the composition of the copolymer (a), preferably at least 80 mol %, more preferentially at least 90 mol %, even more preferentially at least 95 mol % and advantageously at least 98 mol %.

According to a preferred embodiment, the copolymer (a) comprises only units of formula (I) and units of formula (II).

According to one embodiment, the copolymer (a) is chosen from block or random copolymers.

According to a particularly preferred embodiment, the copolymer (a) is a block copolymer.

The group R

of formula (I) is chosen from C₁ to C₃₄, preferably C₄ to C₃₀, more preferentially C₆ to C₂₄ and even more preferentially C₈ to C₂₂ hydrocarbon-based chains, said chains being linear or branched, cyclic or acyclic, preferably acyclic.

The term “hydrocarbon-based chain” means a chain constituted exclusively of carbon and hydrogen atoms, said chain possibly being linear or branched, cyclic, polycyclic or acyclic, saturated or unsaturated, and optionally aromatic or polyaromatic. A hydrocarbon-based chain may comprise a linear or branched part and a cyclic part. It may comprise an aliphatic part and an aromatic part.

The group R₂′ of formula (I) may be a C₁-C₃₄ alkyl, preferably a C₄-C₃₄, preferably C₄-C₃₀, more preferentially C₆-C₂₄ and even more preferentially C₈ to C₁₈ alkyl radical. The alkyl radical is a linear or branched, cyclic or acyclic, preferably acyclic, radical. This alkyl radical may comprise a linear or branched part and a cyclic part.

The group R₂′ of formula (I) is advantageously an acyclic C₁-C₃₄ alkyl, preferably a C₄-C₃₄, preferably C₄-C₃₀, more preferentially C₆-C₂₄ and even more preferentially C₈ to C₁₈ alkyl radical, which is linear or branched, preferably branched.

Mention may be made, nonlimitingly, of alkyl groups such as butyl, octyl, decyl, dodecyl, 2-ethylhexyl, isooctyl, isodecyl and isododecyl.

The group R₂′ of formula (I) may also be an aromatic nucleus, preferably a phenyl or aryl group. Among the aromatic groups, mention may be made, nonlimitingly, of the phenyl or naphthyl group, preferably the phenyl group.

The group R₂′ of formula (I) may, according to another preferred variant, be an aralkyl comprising at least one aromatic nucleus and at least one C₁-C₃₄ alkyl group. Preferably, according to this variant, the group R₂′ is an aralkyl comprising at least one aromatic nucleus and one or more C₄-C₃₄, preferably C₄-C₃₀, more preferentially C₆-C₂₄ and even more preferentially C₈ to C₁₈ alkyl groups.

The aromatic nucleus may be monosubstituted or substituted on several of its carbon atoms. Preferably, the aromatic nucleus is monosubstituted.

The C₁-C₃₄ alkyl group may be in the ortho, meta or para position on the aromatic nucleus, preferably in the para position.

The alkyl radical is a linear or branched, cyclic or acyclic, preferably acyclic, radical.

The alkyl radical is preferably a linear or branched, preferably branched, acyclic radical.

The aromatic nucleus may be directly connected to the oxygen atom, but it may also be connected thereto via an alkyl substituent.

Examples of groups R₂′ that may be mentioned include a benzyl group substituted in the para position with a C₄-C₃₄ and preferably C₄-C₃₀ alkyl group.

Preferably, according to this variant, the group R₂′ of formula (I) is an aralkyl comprising at least one aromatic nucleus and at least one C₄-C₃₄, preferably C₄-C₃₀, more preferentially C₆-C₂₄ and even more preferentially C₈ to C₁₈ alkyl group.

According to a particular embodiment, the group Z of formula (II) is an oxygen atom.

According to a particular embodiment, the group G of formula (II) comprises a quaternary ammonium group and one or more hydroxyl groups.

According to one variant, the group G is chosen from groups bearing at least one quaternary ammonium function obtained by quaternization of a primary, secondary or tertiary amine according to any known process.

The group G may be chosen in particular from groups bearing at least one quaternary ammonium function, obtained by quaternization of at least one amine, imine, amidine, guanidine, aminoguanidine or biguanidine function; heterocyclic groups containing from 3 to 34 atoms and at least one nitrogen atom.

Advantageously, the group G is chosen from groups bearing at least one quaternary ammonium function obtained by quaternization of a tertiary amine.

According to a particular embodiment, the group G of formula (II) is represented by one of the formulae (III) and (IV) below:

in which: X⁻ is chosen from hydroxide and halide ions and organic anions, in particular the acetate ion, R₂ is chosen from cyclic or acyclic, linear or branched C₁ to C₃₄, preferably C₁ to C₁₈, more preferentially C₁ to C₈ and even more preferentially C₂ to C₄ hydrocarbon-based chains, optionally substituted with at least one hydroxyl group; preferably, R₂ is chosen from alkyl groups, optionally substituted with at least one hydroxyl group, it being understood that the group R₂ is connected to the group Z in formula (II), R₃, R₄ and R₅ are identical or different and chosen independently from linear or branched, cyclic or acyclic C₁ to C₁₈ and preferably C₁ to C₁₂ hydrocarbon-based chains, it being understood that the alkyl groups R₃, R₄ and R₅ may contain one or more nitrogen and/or oxygen atoms and/or carbonyl groups and may be connected together in pairs to form one or more rings, R₆ and R₇ are identical or different and chosen independently from linear or branched, cyclic or acyclic C₁ to C₁₈ and preferably C₁ to C₁₂ hydrocarbon-based chains, it being understood that the groups R₆ and R₇ may contain one or more nitrogen and/or oxygen atoms and/or carbonyl groups and may be connected together to form a ring.

The nitrogen and/or oxygen atom(s) may be present in the groups R₃, R₄ and R₅ in the form of ether bridges or amine bridges or in the form of an amine or hydroxyl substituent.

The organic anions of the group X⁻ are advantageously conjugate bases of organic acids, preferably conjugate bases of carboxylic acids, in particular acids chosen from cyclic or acyclic monocarboxylic and polycarboxylic acids. Preferably, the organic anions of the group X⁻ are chosen from conjugate bases of saturated acyclic or aromatic cyclic carboxylic acids. Examples that will be mentioned include methanoic acid, acetic acid, adipic acid, oxalic acid, malonic acid, succinic acid, citric acid, benzoic acid, phthalic acid, isophthalic acid and terephthalic acid.

According to a particular embodiment, the group R₂ is chosen from linear or branched C₁ to C₃₄, preferably C₁ to C₁₈, more preferentially C₁ to C₈ and even more preferentially C₂ to C₄ acyclic alkyl groups, substituted with at least one hydroxyl group.

According to a particular embodiment, the group G of formula (II) comprises a hydrocarbon-based chain substituted with at least one quaternary ammonium group and one or more hydroxyl groups.

Advantageously, the group G of formula (II) is represented by formula (III) in which:

X⁻ is chosen from organic anions, preferably conjugate bases of carboxylic acids, R₂ is chosen from C₁ to C₃₄ hydrocarbon-based chains, preferably C₁ to C₁₈ alkyl groups, R₃, R₄ and R₅ are identical or different and chosen independently from C₁ to C₁₈ hydrocarbon-based chains, optionally substituted with at least one hydroxyl group, it being understood that at least one of the groups R₃, R₄ and R₅ contains at least one hydroxyl group.

According to a particular embodiment, the group R₂ is represented by one of the formulae (V) and (VI) below:

in which: R₈ is chosen from cyclic or acyclic, preferably acyclic, linear or branched C₁ to C₃₂ and preferably C₁ to C₁₆ hydrocarbon-based chains, preferably alkyl groups, R₉ is chosen from hydrogen and C₁ to C₆, C₁ to C₄ alkyl groups, more preferentially hydrogen.

According to a particular embodiment, the unit of formula (I) is obtained from a monomer (m_(a)).

Preferably, the monomer (m_(a)) corresponds to formula (VII) below:

in which R₁′ and R₂′ are as defined above; the variants of R₁′ and R₂′ according to formula (I) as defined above are also preferred variants of formula (VII).

Advantageously, the group R₁′ is a hydrogen atom.

The monomer (m_(a)) is preferably chosen from C₁ to C₃₄, preferably C₄ to C₃₀, more preferentially C₆ to C₂₄ and more preferentially C₈ to C₂₂ alkyl acrylates or methacrylates. The alkyl radical of the acrylate or methacrylate is linear or branched, cyclic or acyclic, preferably acyclic.

Among the alkyl (meth)acrylates that may be used in the manufacture of the copolymer, mention may be made, in a nonlimiting manner, of: n-octyl acrylate, n-octyl methacrylate, n-decyl acrylate, n-decyl methacrylate, n-dodecyl acrylate, n-dodecyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isooctyl acrylate, isooctyl methacrylate, isodecyl acrylate, isodecyl methacrylate.

According to a particular embodiment, the unit of formula (II) is obtained from a monomer (m_(b)).

Preferably, the monomer (m_(b)) is chosen from those of formula (VIII):

in which R₁, Z and Q are as defined above; the preferred variants of R₁, Z and Q according to formula (II) as defined above are also preferred variants of formula (VIII).

According to a particular embodiment, the monomer (m_(b)) is represented by formulae (IX) and (X) below:

in which: R₁ and Z are as defined above; the preferred variants of R₁ and Z according to formula (II) as defined above are also preferred variants of formulae (IX) and (X), X⁻, R₂, R₃, R₄, R₅, R₆ and R₇ are as defined above; the preferred variants of X⁻, R₂, R₃, R₄, R₅, R₆ and R₇ according to formulae (III) and (IV) as defined above are also preferred variants of formulae (IX) and (X).

According to a particular embodiment, at least 70 mol % of the monomers used for the preparation of the copolymer (a) are chosen from the monomers (ma) and the monomers (mb) defined above, preferably at least 80 mol %, more preferentially at least 90 mol %, even more preferentially at least 95 mol % and advantageously at least 98 mol %.

According to a particular preferred embodiment, the copolymer (a) is obtained only from monomers (m_(a)) and monomers (m_(b)).

The copolymer (a) may be prepared according to any known polymerization process. The various polymerization techniques and conditions are widely described in the literature and fall within the general knowledge of a person skilled in the art.

According to a particular embodiment, the copolymer (a) is a block copolymer comprising at least one block A and at least one block B.

International patent application WO 2017/046526 describes block copolymers as defined above and the method for synthesizing same. The content of said document is cited by way of example and/or incorporated by reference into the present patent application.

Preferably, block A is represented by formula (XI) below:

in which p is an integer ranging from 2 to 100, preferably from 5 to 80, preferably from 10 to 70, more preferentially from 20 to 60, R₁′ and R₂′ are as defined above; the variants of R₁′ and R₂′ according to formula (I) as defined above are also preferred variants of formula (XI).

According to a preferred embodiment, p is an integer ranging from 2 to 40 and R

is chosen from C₄ to C₃₀ hydrocarbon-based chains.

According to a preferred embodiment, p is an integer ranging from 2 to 40 and R

is chosen from C₄ to C₃₀ hydrocarbon-based chains, and the copolymer has a number-average molar mass (Mn) ranging from 1000 to 10 000 g·mol⁻¹.

According to one variant, p is an integer greater than 40 and less than or equal to 100, preferably greater than 40 and less than or equal to 80, even more preferentially from 41 to 70 and even more preferentially from 41 to 50.

According to a preferred embodiment of this variant, p is an integer greater than 40 and less than or equal to 100, and R

is chosen from C₄ to C₃₀ hydrocarbon-based chains.

Preferably, block B is represented by formula (XII) below:

in which n is an integer ranging from 2 to 50, preferably from 3 to 40, more preferentially from 4 to 20, even more preferentially from 5 to 10, R₁, Z and G are as defined above; the preferred variants of R₁, Z and Q according to formula (II) as defined above are also preferred variants of formula (XII).

According to a particular embodiment, block B is represented by one of the formulae (XIII) and (XIV) below:

in which: n, Z and R₁ are as described above; the preferred variants of n, Z and R₁ according to formula (II) and (XII) as defined above are also preferred variants of formulae (XIII) and (XIV), X⁻, R₂, R₃, R₄, R₅, R₆ and R₇ are as defined above; the preferred variants X⁻, R₂, R₃,

R₄, R₅, R₆ and R₇ according to formulae (III) and (IV) as defined above are also preferred variants of formulae (XIII) and (XIV).

According to a particular embodiment, block A consists of a chain of structural units derived from at least one monomer (m_(a)) as described above.

According to a particular embodiment, block B consists of a chain of structural units derived from at least one monomer (m_(b)) as described above.

According to a particular embodiment, block A consists of a chain of structural units derived from an alkyl acrylate or alkyl methacrylate monomer (m_(a)) and block B corresponds to formula (XII) described above.

According to a particular embodiment, the block copolymer is obtained by copolymerization of at least one alkyl (meth)acrylate monomer (m_(a)) and of at least one monomer (m_(b)).

The block copolymer may be prepared according to any known polymerization process. The various polymerization techniques and conditions are widely described in the literature and fall within the general knowledge of a person skilled in the art.

It is understood that it would not constitute a departure from the invention if the copolymer according to the invention were obtained from monomers other than (m_(a)) and (m_(b)), provided that the final copolymer corresponds to that of the invention, i.e. a copolymer comprising at least one unit of formula (I) and at least one unit of formula (II) as defined above. For example, it would not constitute a departure from the invention if the copolymer were obtained by copolymerization of monomers other than (m_(a)) and (m_(b)) followed by a post-functionalization.

For example, the units derived from an alkyl (meth)acrylate monomer (m_(a)) may be obtained from a polymethyl (meth)acrylate fragment, by transesterification reaction using an alcohol of chosen chain length to form the expected alkyl group.

For example, the units derived from a monomer (m_(b)) may be obtained by post-functionalization of an intermediate polymer Pi resulting from the polymerization of an intermediate (meth)acrylate or (meth)acrylamide monomer (m_(i)) of formula (XV) defined below, and in which said post-functionalization corresponds to the reaction of said intermediate polymer Pi with a tertiary amine NR₃R₄R₅ or R₆N=R₇, in which R₃, R₄, R₅, R₆ and R₇ are as defined above in formulae (III) and (IV).

The block copolymer may be obtained by block polymerization, preferably by controlled block polymerization, optionally followed by one or more post-functionalizations.

According to a particular embodiment, the block copolymer described above is obtained by controlled block polymerization. The polymerization is advantageously chosen from controlled radical polymerization; for example atom transfer radical polymerization (ATRP); nitroxide-mediated radical polymerization (NMP); degenerative transfer processes such as degenerative iodine transfer polymerization (ITRP: iodine transfer radical polymerization) or reversible addition-fragmentation chain-transfer radical polymerization (RAFT: reversible addition-fragmentation chain transfer); polymerizations derived from ATRP such as polymerizations using initiators for continuous activator regeneration (ICAR) or using activators regenerated by electron transfer (ARGET).

Mention will be made, by way of example, of the publication “Macromolecular engineering by atom transfer radical polymerization”, JACS, 136, 6513-6533 (2014), which describes a controlled block polymerization process for forming block copolymers.

Mention may be made, for example, for NMP, of the identification by C. J. Hawker of an alkoxyamine that is capable of acting as a unimolecular agent, simultaneously providing the reactive initiator radical and the intermediate nitroxide radical in stable form (C. J. Hawker, J. Am. Chem. Soc., 1994, 116, 11185). Hawker also developed a universal NMP initiator (D. Benoit et al., J. Am. Chem. Soc., 1999, 121, 3904).

Reversible addition-fragmentation chain transfer (RAFT) radical polymerization is a living radical polymerization technique. The RAFT technique was discovered in 1988 par by the Australian scientific research organization CSIRO (J. Chiefari et al., Macromolecules, 1998, 31, 5559). The RAFT technique very rapidly became the subject of intensive research by the scientific community since it allows the synthesis of macromolecules having complex architectures, notably block, grafted or comb structures or else star structures, while at the same time making it possible to control the molecular mass of the macromolecules obtained (G. Moad et al., Aust. J. Chem, 2005, 58, 379). RAFT polymerization may be applied to a very wide range of vinyl monomers and under various experimental conditions, including its use for the preparation of water-soluble materials (C. L. McCormick et al., Acc. Chem. Res. 2004, 37, 312). The RAFT process includes the conventional radical polymerization of a substituted monomer in the presence of a suitable chain-transfer agent (CTA or RAFT agent). The RAFT agents commonly used comprise thiocarbonylthio compounds such as dithioesters (J. Chiefari et al., Macromolecules, 1998, 31, 5559), dithiocarbamates (R. T. A. Mayadunne et al., Macromolecules, 1999, 32, 6977; M. Destarac et al., Macromol. Rapid. Commun., 2000, 21, 1035), trithiocarbonates (R. T. A. Mayadunne et al., Macromolecules, 2000, 33, 243) and xanthates (R. Francis et al., Macromolecules, 2000, 33, 4699), which perform the polymerization via a reversible chain-transfer process. The use of a suitable RAFT agent allows the synthesis of polymers having a high degree of functionality and having a narrow molecular weight distribution, i.e. a low polydispersity index (PDI).

Examples of descriptions of RAFT radical polymerizations that may be mentioned include the following documents: WO 1998/01478, WO 1999/31144, WO 2001/77198, WO 2005/00319, WO 2005/000924.

The controlled block polymerization is typically performed in a solvent, under an inert atmosphere, at a reaction temperature generally ranging from 0 to 200° C., preferably from 50° C. to 130° C. The solvent may be chosen from polar solvents, in particular ethers such as anisole (methoxybenzene) or tetrahydrofuran, or apolar solvents, in particular paraffins, cycloparaffins, aromatics and alkylaromatics containing from 1 to 19 carbon atoms, for example benzene, toluene, cyclohexane, methylcyclohexane, n-butene, n-hexane, n-heptane and the like.

For atom transfer radical polymerization (ATRP), the reaction is generally performed under vacuum in the presence of an initiator, a ligand and a catalyst. Examples of ligands that may be mentioned include N,N,N

N

N

pentamethyldiethylenetriamine (PMDETA), 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA), 2,2

bipyridine (BPY) and tris(2-pyridylmethyl)amine (TPMA). Examples of catalysts that may be mentioned include: CuX, CuX₂, with X=Cl, Br and complexes based on ruthenium Ru²⁺/Ru³⁺.

The ATRP polymerization is preferably performed in a solvent chosen from polar solvents.

According to the controlled block polymerization technique, it may also be envisaged to work under pressure.

According to a particular embodiment, the number of equivalents of monomer (m_(a)) of the block A and of monomer (m_(b)) of the block B reacted during the polymerization reaction are identical or different.

The term “number of equivalents” means the amounts (in moles) of material of the monomers (m_(a)) of block A and of the monomers (m_(b)) of block B used during the polymerization reaction.

The number of equivalents of monomer (m_(a)) of the block A is preferably from 2 to 100 eq, preferably from 5 to 80 eq, preferably from 10 to 70 eq and more preferentially from 20 to 60 eq.

The number of equivalents of monomer (m_(b)) of the block B is preferably from 2 to 50 eq, preferably from 3 to 40 eq, more preferentially from 4 to 20 eq and even more preferentially from 5 to 10 eq.

The number of equivalents of monomer m_(a) of the block A is advantageously greater than or equal to that of the monomer m_(b) of the block B.

In addition, the weight-average molar mass M_(w) of the block A or of the block B is preferably less than or equal to 15 000 g·mol.⁻¹, more preferentially less than or equal to 10 000 g·mol.⁻¹.

The block copolymer advantageously comprises at least one sequence of blocks AB, ABA or BAB in which said blocks A and B form a sequence without the presence of an intermediate block of different chemical nature.

Other blocks may optionally be present in the block copolymer described previously provided that these blocks do not fundamentally change the nature of the block copolymer. However, block copolymers containing only blocks A and B will be preferred.

Advantageously, A and B represent at least 70% by mass, preferably at least 90% by mass, more preferentially at least 95% by mass and even more preferentially at least 99% by mass of the block copolymer.

According to a particular embodiment, the block copolymer is a diblock copolymer.

According to another particular embodiment, the block copolymer is a triblock copolymer containing alternating blocks comprising two blocks A and one block B (ABA) or comprising two blocks B and one block A (BAB).

According to a particular embodiment, the block copolymer also comprises an end chain I consisting of a cyclic or acyclic, saturated or unsaturated, linear or branched C₁ to C₃₂, preferably C₄ to C₂₄ and more preferentially C₁₀ to C₂₄ hydrocarbon-based chain.

The term “cyclic hydrocarbon-based chain” means a hydrocarbon-based chain of which at least part is cyclic, notably aromatic. This definition does not exclude hydrocarbon-based chains comprising both an acyclic part and a cyclic part.

The end chain I may comprise an aromatic hydrocarbon-based chain, for example benzene-based, and/or a saturated and acyclic, linear or branched hydrocarbon-based chain, in particular an alkyl chain.

The end chain I is preferably chosen from alkyl chains, which are preferably linear, more preferentially alkyl chains of at least 4 carbon atoms and even more preferentially of at least 12 carbon atoms.

For the ATRP polymerization, the end chain I is located in the end position of the block copolymer. It may be introduced into the block copolymer by means of the polymerization initiator. Thus, the end chain I may advantageously constitute at least part of the polymerization initiator and is positioned within the polymerization initiator so as to make it possible to introduce, during the first step of polymerization initiation, the end chain I in the end position of the block copolymer.

The polymerization initiator is chosen, for example, from the free-radical initiators used in the ATRP polymerization process. These free-radical initiators well known to those skilled in the art are notably described in the article “Atom transfer radical polymerization: current status and future perspectives, Macromolecules, 45, 4015-4039, 2012”.

The polymerization initiator is chosen, for example, from alkyl esters of a carboxylic acid substituted with a halide, preferably a bromine in the alpha position, for example ethyl 2-bromopropionate, ethyl α-bromoisobutyrate, benzyl chloride or bromide, ethyl α-bromophenylacetate and chloroethylbenzene. Thus, for example, ethyl 2-bromopropionate may make it possible to introduce into the copolymer the end chain I in the form of a C₂ alkyl chain and benzyl bromide in the form of a benzyl group.

For the RAFT polymerization, the transfer agent may conventionally be removed from the copolymer at the end of polymerization according to any known process.

According to one variant, the end chain I may also be obtained in the copolymer by RAFT polymerization according to the methods described in the article by Moad, G. et al., Australian Journal of Chemistry, 2012, 65, 985-1076. For example, the end chain I may be introduced by aminolysis when a transfer agent is used to give a thiol function. Examples that may be mentioned include transfer agents of thiocarbonylthio, dithiocarbonate, xanthate, dithiocarbamate and trithiocarbonate type, for example S,S₀-dibenzyl trithiocarbonate (DBTTC), S,S-bis(α,α

dimethyl-α

acetic acid) trithiocarbonate (BDMAT) or 2-cyano-2-propyl benzodithioate (CPD).

According to a known process, the transfer agent may be cleaved at the end of polymerization by reacting a cleaving agent such as C2-C6 alkylamines; the end function of the copolymer may in this case be a thiol group —SH.

According to another process described in patent EP 1 751 194, the sulfur of the copolymer obtained by RAFT polymerization introduced by the sulfur-based transfer agent such as thiocarbonylthio, dithiocarbonate, xanthate, dithiocarbamate and trithiocarbonate may be converted so as to remove the sulfur from the copolymer.

According to a particular embodiment, the block copolymer is a diblock copolymer. The block copolymer structure may be of the IAB or IBA type, advantageously IAB. The end chain I may be directly linked to block A or B according to the structure IAB or IBA, respectively, or may be connected via a bonding group, for example an ester, amide, amine or ether function. The bonding group then forms a bridge between the end chain I and block A or B.

According to a particular embodiment, the block copolymer may also be functionalized at the chain end according to any known process, notably by hydrolysis, aminolysis and/or nucleophilic substitution.

The term “aminolysis” means any chemical reaction in which a molecule is split into two parts by reaction of an ammonia or amine molecule. A general example of aminolysis consists in replacing a halogen of an alkyl group by reaction with an amine, with removal of hydrogen halide. Aminolysis may be used, for example, for an ATRP polymerization which produces a copolymer bearing a halide in the end position or for a RAFT polymerization to convert the thio, dithio or trithio bond introduced into the copolymer by the RAFT transfer agent into a thiol function.

An end chain I′ may thus be introduced by post-functionalization of the block copolymer obtained by controlled block polymerization of the monomers (m_(a)) and (m_(b)) described above.

The end chain I′ advantageously comprises a linear or branched, cyclic or acyclic C₁ to C₃₂, preferably C₁ to C₂₄ and more preferentially C₁ to C₁₀ hydrocarbon-based chain, even more preferentially an alkyl group, optionally substituted with one or more groups containing at least one heteroatom chosen from N and O, preferably N.

For an ATRP polymerization using a metal halide as catalyst, this functionalization may be performed, for example, by treating the copolymer IAB or IBA obtained by ATRP with a primary C₁ to C₃₂ alkylamine or a C₁ to C₃₂ alcohol under mild conditions so as not to modify the functions present on blocks A, B and I.

The quaternary ammonium group of block B described above may be acyclic or cyclic.

The acyclic quaternary ammonium group is advantageously chosen from trialkylammonium, iminium, amidinium, formamidinium, guanidinium and biguanidinium quaternary salts, preferably trialkylammonium quaternary salts.

The cyclic quaternary ammonium group is advantageously chosen from heterocyclic compounds containing at least one nitrogen atom chosen in particular from pyrrolinium, pyridinium, imidazolium, triazolium, triazinium, oxazolium and isoxazolium quaternary salts.

The quaternary ammonium group of block B is advantageously a quaternary ammonium, even more advantageously a quaternary trialkylammonium salt.

According to a preferred variant, at least one of the alkyl groups of the quaternary ammonium of block B is substituted with a hydroxyl group.

According to a particular embodiment, block B is preferably derived from a monomer (m_(b)) obtained by the reaction:

of a tertiary amine of formula NR₃R₄R₅ or R₆N=R₇ in which R₃, R₄, R₅, R₆ and R₇ are as described above, and

of a (meth)acrylate or (meth)acrylamide intermediate monomer m_(i) of formula (XV) below:

in which: Z, R₈ and R₉ are as described above; the preferred variants of Z, R₁, R₈ and R₉ according to formulae (II), (V) and (VI) as defined above are also preferred variants of formula (XV).

According to another particular embodiment, block B is obtained by post-functionalization of an intermediate polymer Pi comprising at least one block P of formula (XVI) below:

in which: n, Z, R₁, R₈ and R₉ are as described above; the preferred variants of n, Z, R₁, R₈ and R₉ according to formulae (II), (V), (VI) and (XVII) as defined above are also preferred variants of formula (XVI).

The post-functionalization corresponds to the reaction of the intermediate polymer Pi with a tertiary amine of formula NR₃R₄R₅ or R₆N=R₇ in which R₃, R₄, R₅, R₆ and R₇ are as described previously.

The tertiary amine may be chosen, for example, from acyclic tertiary amines, preferably quaternizable trialkylamines, guanidines and imines. The tertiary amine is advantageously chosen from trialkylamines, in particular those in which the alkyl groups are identical or different and chosen independently from linear or branched, cyclic or acyclic, preferably acyclic, C₁ to C₁₈ and preferably C₁ to C₁₂ alkyls.

According to one variant, the tertiary amine may be chosen from cyclic tertiary amines, preferably quaternizable pyrrolines, pyridines, imidazoles, triazoles, guanidines, imines, triazines, oxazoles and isoxazoles.

The intermediate polymer Pi may also comprise at least one block A as described above.

According to a particular preferred embodiment, block B of formula (XII) is obtained by quaternization, according to any known process, of a tertiary amine corresponding to the quaternary ammonium group of block B of formula NR₃R₄R₅ or R₆N=R₇ in which R₃, R₄, R₅, R₆ and R₇ are as defined above.

The quaternization step may be performed before the copolymerization reaction, on an intermediate monomer bearing the tertiary amine, for example by reaction with an alkyl halide or an epoxide (oxirane) according to any known process, optionally followed by an anion exchange reaction.

The quaternization step may also be performed by post-functionalization of an intermediate polymer bearing the tertiary amine, for example by reaction with an alkyl halide optionally followed by an anion exchange reaction. An example of a quaternization that may be mentioned is a post-functionalization reaction of an intermediate polymer bearing the tertiary amine, by reaction with an epoxide (oxirane) according to any known process.

It is preferred to copolymerize intermediate monomers bearing a tertiary amine function and then, in a second step, to functionalize the intermediate copolymer obtained by quaternization of the tertiary amine present in the intermediate copolymer, rather than to copolymerize monomers that are already quaternized.

In addition, quaternization involving an epoxide will preferably be performed.

The fuel additive composition may advantageously comprise from 5% to 99% by mass, preferably from 10% to 80% and more preferentially from 25% to 70% of copolymer (a) as described previously.

The Succinimide Compound (b)

The fuel additive composition according to the invention also comprises at least one chemical compound selected from succinimides substituted with a hydrocarbon-based chain (b).

Preferably, the succinimide compound (b) is substituted with a hydrocarbon-based chain, preferably a C₈-C₅₀₀ and more preferentially C₁₂-C₁₅₀ chain.

More preferentially, the succinimide compound substituted with a hydrocarbon-based chain (b) is chosen from polyisobutene succinimides.

Polyisobutene succinimides may be obtained by reaction of a succinic acid or anhydride, substituted with a polyisobutenyl chain, with an amine compound.

Preferably, the polyisobutenyl chain substituting the succinic acid or anhydride has a number-average molecular mass ranging from 200 to 5000 g/mol, preferably from 400 to 3000, more preferentially ranging from 500 to 2500 and even more preferentially ranging from 800 to 1500, the number-average molecular mass being determined by gel permeation chromatography (GPC), also referred to as size exclusion chromatography (SEC), from the starting polymer.

The preparation of succinic anhydrides substituted with a polyisobutenyl chain is widely described in the literature. For example, documents U.S. Pat. Nos. 3,361,673 and 3,018,250 describe the preparation thereof by high-temperature reaction between a polyisobutene and maleic anhydride, or else by reaction between a halogenated, notably chlorinated, polyisobutene and maleic anhydride. Mention may also be made of document GB 949 981 which describes the preparation of such compounds from a mixture of polyisobutenyl and succinic anhydride and into which chlorine is injected.

In any case, the product obtained consists of a complex mixture of unreacted polymers and of succinic anhydrides substituted with a polyisobutene chain in which the polyisobutenyl substituent is bonded to at least one of the carbons located alpha to the carbonyl groups of the succinic anhydride.

According to one variant, the amine compound used for the preparation of the polyisobutene succinimide is ammonia NH₃.

According to a preferred variant, the amine compound used for the preparation of the polyisobutene succinimide is a C₁-C₅₀ and preferably C₂-C₃₀ hydrocarbon-based compound comprising at least one amine function, preferably a primary amine function.

According to a first embodiment, the amine function is substituted with at least one optionally substituted heterocycle, said heterocycle comprising at least two carbon atoms and at least one nitrogen atom, preferably at least two nitrogen atoms, more preferentially at least three nitrogen atoms.

Preferably, according to this first embodiment, the amine function is substituted with an optionally substituted triazole group.

More preferentially, according to this first embodiment, the amine compound corresponds to formula (XVII) below:

in which R₁₃ is chosen from the group consisting of a hydrogen atom, a linear or branched C₁ to C₈ aliphatic hydrocarbon-based group and a carboxylic acid group (—CO₂H).

Preferably, R₁₃ is a hydrogen atom.

According to a second embodiment, the amine compound consists of a linear or branched C₁-C₅₀ and preferably C₂-C₃₀ hydrocarbon-based chain comprising at least one amine group.

Preferably, according to this second embodiment, the amine compound is chosen from the polyalkylenepolyamines of formula (XVIII) below:

H₂N—(R₁₀NH)_(q)—H  (XVIII)

in which:

the groups R₁₀ are chosen independently from C₁-C₅, preferably C₂-C₃, alkylene chains, and

q is an integer ranging from 1 to 10 and preferably from 3 to 5.

According to a preferred embodiment, the groups R₁₀ are all identical.

Even more preferentially, the polyalkylenepolyamine is chosen from the polyethylenepolyamines of formula (XIX) below:

H₂N—(CH₂CH₂NH)_(q)—H  (XIX)

in which q is an integer ranging from 1 to 10, preferably from 3 to 5.

Advantageously, the polyethylenepolyamine is chosen from ethylenediamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine. More advantageously, the polyethylenepolyamine is tetraethylenepentamine.

Preferably, the succinic acid or succinic anhydride, substituted with a polyisobutene chain, and the amine compound are introduced in a mole ratio ranging from 0.2:1 to 5:1, preferably ranging from 0.2:1 to 2.5:1, even more preferably ranging from 1:1 to 2:1.

The reaction between the succinic acid or anhydride substituted with a polyisobutenyl chain and the amine compound is preferably performed at a temperature of at least 80° C., preferably at a temperature ranging from 125 to 250° C.

Preferably, the polyisobutene succinimide compound corresponds to formula (XX) below:

in which:

R₁₂ is a polyisobutenyl chain, and

R₁₁ is a hydrogen atom or a C₁-C₅₀ and preferably C₂-C₃₀ hydrocarbon-based group comprising at least one nitrogen atom.

According to a first embodiment, the group R₁₁ comprises at least one optionally substituted heterocycle, said heterocycle comprising at least two carbon atoms and at least one nitrogen atom, preferably at least two nitrogen atoms, more preferentially at least three nitrogen atoms.

Preferably, according to this first embodiment, the group R₁₁ consists of an optionally substituted triazole group.

More preferentially, according to this first embodiment, the group R₁₁ corresponds to formula (XXI) below:

in which R₁₃ is chosen from the group consisting of a hydrogen atom, a linear or branched C₁ to C₈ aliphatic hydrocarbon-based group and a carboxylic acid group (—CO₂H).

Preferably, R₁₃ is a hydrogen atom.

According to a second embodiment, the group R₁₁ consists of a linear or branched C₁-C₅₀ and preferably C₂-C₃₀ hydrocarbon-based group comprising at least one amine group.

Preferably, according to this second embodiment, the group R₁₁ consists of a polyalkylenepolyamine chain of formula (XXII) below:

—(R₁₀NH)_(q)—H(XXII)

in which:

the groups R₁₀ are chosen independently from C₁-C₅, preferably C₂-C₃, alkylene chains, and

q is an integer ranging from 1 to 10 and preferably from 3 to 5.

It is important to note that polyalkylenepolyamines are commercially available in the form of complex mixtures also comprising, in small amounts, cyclic compounds such as piperazines. Consequently, the detergent additives of polyisobutene succinimide type described previously are available in the form of mixtures that may also comprise, in a minor amount, unreacted polyolefins, reaction solvent or byproducts. It is common in the literature to refer to these mixtures by the term “alkenyl succinimide detergent”.

The fuel additive composition may advantageously comprise from 5% to 99% by mass, preferably from 10% to 80% and more preferentially from 25% to 70% of succinimide compound (b) as described previously.

Advantageously, in the fuel additive composition according to the invention, the mass ratio between the copolymer(s) (a) and the succinimide compound (b) ranges from 5:95 to 95:5, preferably from 10:90 to 90:10.

Uses

The fuel additive composition described above is particularly advantageous when it is used as detergent additive in a liquid fuel for an internal combustion engine.

The term “detergent additive for liquid fuel” means an additive which is incorporated in small amount into the liquid fuel and produces an effect on the cleanliness of said engine when compared with said liquid fuel not specially supplemented.

The fuel additive composition described above is also particularly advantageous when it is used as demulsifying additive in a liquid fuel for an internal combustion engine.

The term “demulsifying additive” means an additive which is incorporated in small amount into the liquid fuel and which makes it possible to improve the separation of the water and the fuel when said fuel contains water.

In particular, the use of the fuel additive composition according to the invention in a liquid fuel makes it possible simultaneously to maintain the cleanliness of at least one of the internal parts of the internal combustion engine and/or to clean at least one of the internal parts of the internal combustion engine, relative to a fuel that is not specially supplemented.

The use of the additive composition according to the invention also makes it possible to improve the separation of the water and the fuel when said fuel contains water.

The term “improve the separation of the water and the fuel” means accelerating the separation, and/or increasing the degree of separation, of the fuel and of the residual water present in this fuel, compared to a fuel comprising only:

a succinimide compound (b) as defined above, or

a copolymer (a) as defined above.

The liquid fuel is advantageously derived from one or more sources chosen from the group consisting of mineral, animal, plant and synthetic sources. Oil will preferably be chosen as mineral source.

The liquid fuel is preferably chosen from hydrocarbon-based fuels and fuels that are not essentially hydrocarbon-based, alone or as a mixture.

The term “hydrocarbon-based fuel” means a fuel constituted of one or more compounds constituted solely of carbon and hydrogen.

The term “fuel not essentially hydrocarbon-based” means a fuel constituted of one or more compounds not essentially constituted of carbon and hydrogen, i.e. which also contain other atoms, in particular oxygen atoms.

The hydrocarbon-based fuels notably comprise middle distillates with a boiling point ranging from 100 to 500° C. or lighter distillates with a boiling point in the gasoline range. These distillates may be chosen, for example, from the distillates obtained by direct distillation of crude hydrocarbons, vacuum distillates, hydrotreated distillates, distillates derived from the catalytic cracking and/or hydrocracking of vacuum distillates, distillates resulting from conversion processes such as ARDS (atmospheric residue desulfurization) and/or viscoreduction, and distillates derived from the upgrading of Fischer-Tropsch fractions. The hydrocarbon-based fuels are typically gasolines and gas oils (also known as diesel fuel).

Gasolines in particular comprise any commercially available fuel composition for spark ignition engines. A representative example that may be mentioned is the gasolines corresponding to the standard NF EN 228. Gasolines generally have octane numbers that are high enough to avoid pinking. Typically, the fuels of gasoline type sold in Europe, in accordance with the standard NF EN 228, have a motor octane number (MON) of greater than 85 and a research octane number (RON) of at least 95. Fuels of gasoline type generally have an RON ranging from 90 to 100 and an MON ranging from 80 to 90, the RON and MON being measured according to the standard ASTM D 2699-86 or D 2700-86.

Gas oils (diesel fuels) in particular comprise any commercially available fuel composition for diesel engines. A representative example that may be mentioned is the gas oils corresponding to the standard NF EN 590.

Fuels that are not essentially hydrocarbon-based notably comprise oxygen-based compounds, for example distillates resulting from the BTL (biomass to liquid) conversion of plant and/or animal biomass, taken alone or in combination; biofuels, for example plant and/or animal oils and/or ester oils; biodiesels of animal and/or plant origin and bioethanols.

The mixtures of hydrocarbon-based fuel and of fuel that is not essentially hydrocarbon-based are typically gas oils of B_(x) type or gasolines of E_(x) type.

The term “gas oil of B_(x) type for diesel engines” means a gas oil fuel which contains x % (v/v) of plant or animal oil esters (including spent cooking oils) transformed via a chemical process known as transesterification, obtained by reacting this oil with an alcohol so as to obtain fatty acid esters (FAE). With methanol and ethanol, fatty acid methyl esters (FAME) and fatty acid ethyl esters (FAEE) are obtained, respectively. The letter “B” followed by a number indicates the percentage of FAE contained in the gas oil. Thus, a B99 contains 99% of FAE and 1% of middle distillates of fossil origin (mineral source), B20 contains 20% of FAE and 80% of middle distillates of fossil origin, etc. A distinction is thus made between gas oils of the B₀ type which do not contain any oxygen-based compounds, and gas oils of the Bx type which contain x % (v/v) of esters of plant oils or of carboxylic acids, usually methyl esters (POME or FAME). When the FAE is used alone in engines, the fuel is designated by the term B100.

The term “gasoline of E_(x) type for spark ignition engines” means a gasoline fuel which contains x % (v/v) of oxygen-based compounds, generally ethanol, bioethanol and/or tert-butyl ethyl ether (TBEE).

The sulfur content of the liquid fuel is preferably less than or equal to 5000 ppm, preferably less than or equal to 500 ppm and more preferentially less than or equal to 50 ppm, or even less than 10 ppm and advantageously sulfur-free.

The fuel additive composition described above is used in the liquid fuel in a content advantageously of at least 10 ppm, preferably at least 50 ppm, more preferentially in a content from 10 to 5000 ppm, even more preferentially from 10 to 1000 ppm.

According to a particular embodiment, the use of a fuel additive composition as described previously in the liquid fuel makes it possible to maintain the cleanliness of at least one of the internal parts of the internal combustion engine and/or to clean at least one of the internal parts of the internal combustion engine.

The use of the fuel additive composition in the liquid fuel makes it possible in particular to limit or prevent the formation of deposits in at least one of the internal parts of said engine (“keep-clean” effect) and/or to reduce the existing deposits in at least one of the internal parts of said engine (“clean-up” effect).

Thus, the use of the fuel additive composition according to the invention in the liquid fuel makes it possible, when compared with liquid fuel that is not specially supplemented, to limit or prevent the formation of deposits in at least one of the internal parts of said engine or to reduce the existing deposits in at least one of the internal parts of said engine.

Advantageously, the use of the fuel additive composition according to the invention in the liquid fuel makes it possible to observe both effects simultaneously, limitation (or prevention) and reduction of deposits (“keep-clean” and “clean-up” effects).

The deposits are distinguished as a function of the type of internal combustion engine and of the location of the deposits in the internal parts of said engine.

According to a particular embodiment, the internal combustion engine is a spark ignition engine, preferably with direct injection (DISI: direct-injection spark ignition engine). The deposits targeted are located in at least one of the internal parts of said spark ignition engine. The internal part of the spark ignition engine that is kept clean (keep-clean) and/or cleaned (clean-up) is advantageously chosen from the engine intake system, in particular the intake valves (IVD: intake valve deposit), the combustion chamber (CCD: combustion chamber deposit, or TCD: total chamber deposit) and the fuel injection system, in particular the injectors of an indirect injection system (PFI: port fuel injector) or the injectors of a direct injection system (DISI).

According to another particular embodiment, the internal combustion engine is a diesel engine, preferably a direct-injection diesel engine, in particular a diesel engine with a common-rail injection system (CRDI: common-rail direct injection). The deposits targeted are located in at least one of the internal parts of said diesel engine.

Advantageously, the deposits targeted are located in the injection system of the diesel engine, preferably located on an external part of an injector of said injection system, for example the injector tip, and/or on an internal part of an injector of said injection system (IDID: internal diesel injector deposits), for example on the surface of an injector needle.

The deposits may be constituted of coking-related deposits and/or deposits of soap and/or lacquering type.

The fuel additive composition as described previously may advantageously be used in the liquid fuel to reduce and/or prevent power loss due to the formation of the deposits in the internal parts of a direct-injection diesel engine, said power loss being determined according to the standardized engine test method CEC F-98-08.

The fuel additive composition as described previously may advantageously be used in the liquid fuel to reduce and/or prevent restriction of the fuel flow emitted by the injector of a direct-injection diesel engine during its functioning, said flow restriction being determined according to the standardized engine test method CEC F-23-1-01.

Advantageously, the use of the fuel additive composition as described above makes it possible, when compared with liquid fuel that is not specially supplemented, to limit or prevent the formation of deposits on at least one type of deposit described previously and/or to reduce the existing deposits on at least one type of deposit described previously.

According to a particular embodiment, the use of the fuel additive composition described above also makes it possible to reduce the fuel consumption of an internal combustion engine.

According to another particular embodiment, the use of the fuel additive composition described above also makes it possible to reduce the pollutant emissions, in particular the particle emissions of the internal combustion engine.

Advantageously, the use of the fuel additive composition according to the invention makes it possible to reduce both the fuel consumption and the pollutant emissions.

The fuel additive composition described above may be used alone or mixed with other fuel additives in the form of an additive concentrate.

The fuel additive composition according to the invention may be added to the liquid fuel in a refinery and/or may be incorporated downstream of the refinery and/or optionally as a mixture with other additives in the form of an additive concentrate, also known by the common name “additive package”.

According to one embodiment, the fuel additive composition described above is used as a mixture with an organic liquid in the form of a concentrate.

According to a particular embodiment, a concentrate for fuel comprises one or more copolymers (a) and one or more succinimide compounds (b) as described above, as a mixture with an organic liquid.

The organic liquid is inert with respect to the copolymer (a) and the succinimide compound (b) described above and miscible in the liquid fuel described previously. The term “miscible” describes the fact that the copolymer (a), the succinimide compound (b) and the organic liquid form a solution or a dispersion so as to facilitate the mixing of the additive composition according to the invention in the liquid fuels according to the standard fuel supplementation processes.

The organic liquid is advantageously chosen from aromatic hydrocarbon-based solvents such as the solvent sold under the name Solvesso, alcohols, ethers and other oxygen-based compounds and paraffinic solvents such as hexane, pentane or isoparaffins, alone or as a mixture.

The concentrate may advantageously comprise from 5% to 99% by mass, preferably from 10% to 80% and more preferentially from 25% to 70% of copolymer (a) as described previously.

The concentrate may typically comprise from 1% to 95% by mass, preferably from 10% to 70% and more preferentially from 25% to 60% of organic liquid, the remainder corresponding to the copolymer (a) and to the succinimide compound (b), it being understood that the concentrate may comprise one or more copolymers (a) and one or more succinimide compounds (b) as described above.

In general, the solubility of the copolymer (a) in the organic liquids and the liquid fuels described previously will notably depend on the weight-average and number-average molar masses M_(w) and M_(n), respectively, of the copolymer. The average molar masses M_(w) and M_(n) of the copolymer (a) will be chosen so that the copolymer (a) is soluble in the liquid fuel and/or the organic liquid of the concentrate for which it is intended.

The average molar masses M_(w) and M_(n) of the copolymer (a) may also have an influence on the efficiency of the fuel additive composition according to the invention as a detergent additive. The average molar masses M_(w) and M_(n) will thus be chosen so as to optimize the effect of the copolymer (a), notably the detergency effect (engine cleanliness) in the liquid fuels described above.

According to a particular embodiment, the copolymer (a) advantageously has a weight-average molar mass (Mw) ranging from 500 to 30 000 g·mol⁻¹, preferably from 1000 to 10 000 g·mol⁻¹, more preferentially less than or equal to 4000 g·mol⁻¹, and/or a number-average molar mass (Mn) ranging from 500 to 15 000 g·mol⁻¹, preferably from 1000 to 10 000 g·mol⁻¹, more preferentially from 3000 to 8000 g·mol⁻¹, even more preferentially from 3000 to 7000 g·mol⁻¹ and in particular from 4000 to 5000 g·mol⁻¹. According to one variant, the number-average molar mass (Mn) is less than or equal to 4000 g·mol⁻¹. The number-average and weight-average molar masses are measured by size exclusion chromatography (SEC). The operating conditions of SEC, notably the choice of the solvent, will be chosen as a function of the chemical functions present in the copolymer.

According to a particular embodiment, the fuel additive composition according to the invention is used in the form of an additive concentrate in combination with at least one other fuel additive for an internal combustion engine other than the copolymer (a) and the succinimide compound (b) described previously.

The additive concentrate may typically comprise one or more other additives chosen from detergent additives other than the copolymer and the succinimide compound described above, for example from anticorrosion agents, dispersants, demulsifiers other than the succinimide compound described above, antifoams, biocides, reodorants, cetane boosters, friction modifiers, lubricity additives or oiliness additives, combustion aids (catalytic soot and combustion promoters), agents for improving the cloud point, the flow point or the FLT (filterability limit temperature), sedimentation-inhibiting agents, antiwear agents and conductivity modifiers.

Among these additives, mention may be made in particular of:

a) cetane boosters, notably (but not limitingly) chosen from alkyl nitrates, preferably 2-ethylhexyl nitrate, aryl peroxides, preferably benzyl peroxide, and alkyl peroxides, preferably tert-butyl peroxide; b) antifoam additives, notably (but not limitingly) chosen from polysiloxanes, oxyalkylated polysiloxanes and fatty acid amides derived from plant or animal oils. Examples of such additives are given in EP861882, EP663000 and EP736590; c) cold flow improvers (CFI) chosen from copolymers of ethylene and of an unsaturated ester, such as ethylene/vinyl acetate (EVA), ethylene/vinyl propionate (EVP), ethylene/vinyl ethanoate (EVE), ethylene/methyl methacrylate (EMMA) and ethylene/alkyl fumarate copolymers described, for example, in U.S. Pat. Nos. 3,048,479, 3,627,838, 3,790,359, 3,961,961 and EP261957; d) lubricity additives or antiwear agents, notably (but not limitingly) chosen from the group constituted by fatty acids and ester or amide derivatives thereof, notably glyceryl monooleate, and monocyclic and polycyclic carboxylic acid derivatives. Examples of such additives are given in the following documents: EP680506, EP860494, WO98/04656, EP915944, FR2772783, FR2772784; e) cloud point additives, notably (but not limitingly) chosen from the group constituted by long-chain olefin/(meth)acrylic ester/maleimide terpolymers, and fumaric/maleic acid ester polymers. Examples of such additives are given in FR2528051, FR2528051, FR2528423, EP112195, EP172758, EP271385 and EP291367; f) detergent additives, notably (but not limitingly) chosen from the group constituted by polyetheramines and quaternary ammonium salts; for example those described in U.S. Pat. No. 4,171,959 and WO2006135881; g) cold workability polyfunctional additives chosen from the group constituted by polymers based on olefin and alkenyl nitrate as described in EP573490.

These other additives are generally added in an amount ranging from 10 to 1000 ppm (each), preferably from 100 to 1000 ppm (each).

The mole ratio and/or mass ratio between monomer m_(b) and monomer m_(a) and/or between block A and B in the block copolymer described above will be chosen so that the copolymer is soluble in the fuel and/or the organic liquid of the concentrate for which it is intended. Similarly, this ratio may be optimized as a function of the fuel and/or of the organic liquid so as to obtain the best effect on the engine cleanliness.

Optimizing the mole ratio and/or mass ratio may be performed via routine tests accessible to those skilled in the art.

The mole ratio between monomer m_(b) and monomer m_(a) or between blocks A and B in the block copolymer described above advantageously ranges from 1:10 to 10:1, preferably from 1:2 to 2:1 and more preferentially from 1:0.5 to 0.5:2.

According to a particular embodiment, a fuel composition is prepared according to any known process by supplementing the liquid fuel described previously with a fuel additive composition as described above.

According to a particular embodiment, a fuel composition comprises:

(1) a fuel as described above, and (2) a fuel additive composition as described previously.

The fuel (1) is chosen in particular from hydrocarbon-based fuels and fuels that are not essentially hydrocarbon-based described previously, taken alone or as a mixture.

The introduction, notably the combustion, of this fuel composition comprising a fuel additive composition according to the invention into an internal combustion engine produces an effect on the cleanliness of the engine when compared with the liquid fuel that is not specially supplemented. The combustion of this fuel composition makes it possible in particular to prevent and/or reduce the fouling of the internal parts of said engine. These effects on engine cleanliness are as described previously in the context of the use of the fuel additive composition.

Moreover, the introduction of the additive composition according to the invention into an internal combustion engine fuel as defined above makes it possible to produce an effect on the demulsifying of said fuel, when compared with a fuel comprising only the copolymer (a) or only the succinimide compound (b).

According to a particular embodiment, the combustion of the fuel composition comprising such a fuel additive composition in an internal combustion engine also makes it possible to reduce the fuel consumption and/or the pollutant emissions.

The fuel additive composition according to the invention is preferably incorporated in low amount into the liquid fuel described previously, the amount of fuel additive composition being sufficient firstly to produce a detergent effect and secondly a demulsifying effect as described above.

According to a particular embodiment, the fuel composition advantageously comprises at least 1 ppm, preferably from 10 to 5000 ppm, more preferentially from 20 to 2000 ppm and in particular from 50 to 500 ppm of copolymer(s) (a).

According to an advantageous embodiment, the fuel composition advantageously comprises from 1 to 1000 ppm, preferably from 5 to 500 ppm, more preferentially from 10 to 200 ppm and even more preferentially from 20 to 100 ppm of copolymer(s) (a).

The fuel composition advantageously comprises from 1 to 1000 ppm, preferably from 5 to 500 ppm, more preferentially from 10 to 200 ppm and even more preferentially from 20 to 100 ppm of succinimide compounds substituted with a hydrocarbon-based chain (b).

Besides the fuel additive composition described above, the fuel composition may also comprise one or more additives other than the copolymer (a) and the succinimide compound (b) present in the fuel additive composition according to the invention. These additives are notably chosen from the other known detergent additives, for example from anticorrosion agents, dispersants, other demulsifiers, antifoams, biocides, reodorants, cetane boosters, friction modifiers, lubricity additives or oiliness additives, combustion aids (catalytic soot and combustion promoters), agents for improving the cloud point, the flow point or the FLT, sedimentation-inhibiting agents, antiwear agents and/or conductivity modifiers.

The additives other than the copolymer (a) and the succinimide compound (b) present in the fuel additive composition according to the invention are, for example, the fuel additives listed above.

According to a particular embodiment, a process for maintaining the cleanliness of (keep-clean) and/or for cleaning (clean-up) at least one of the internal parts of an internal combustion engine comprises the preparation of a fuel composition by supplementation of a fuel with a fuel additive composition as described above and the introduction, notably the combustion, of said fuel composition in the internal combustion engine.

According to a particular embodiment, the internal combustion engine is a spark ignition engine, preferably a direct-injection spark ignition (DISI) engine.

The internal part of the spark ignition engine that is kept clean and/or cleaned is preferably chosen from the engine intake system, in particular the intake valves (IVD), the combustion chamber (CCD or TCD) and the fuel injection system, in particular the injectors of an indirect injection system (PFI) or the injectors of a direct injection system (DISI).

According to another particular embodiment, the internal combustion engine is a diesel engine, preferably a direct-injection diesel engine, in particular a diesel engine with common-rail injection systems (CRDI).

The internal part of the diesel engine that is kept clean (keep-clean) and/or cleaned (clean-up) is preferably the injection system of the diesel engine, preferably an external part of an injector of said injection system, for example the injector tip, and/or one of the internal parts of an injector of said injection system, for example the surface of an injector needle.

The process for maintaining the cleanliness (keep-clean) and/or for cleaning (clean-up) comprises the successive steps of:

1) determining the most suitable supplementation for the fuel, said supplementation corresponding to the selection of the fuel additive composition described above to be incorporated in combination, optionally, with other fuel additives as described previously and determining the degree of treatment necessary to achieve a given specification relative to the detergency of the fuel composition; 2) incorporating into the fuel the selected fuel additive composition in the amount determined in step 1) and, optionally, the other fuel additives.

The selection of the fuel additive composition more particularly corresponds to the selection firstly of one or more copolymers (a) as described above and secondly of one or more succinimide compounds (b) as described previously, but also to the determination of the ratio in which these compounds will be introduced in order to prepare a fuel additive composition according to the invention.

The copolymer(s) (a) and the succinimide compound(s) (b) may be incorporated into the fuel, alone or as a mixture, successively or simultaneously.

Alternatively, the fuel additive composition may be used in the form of a concentrate or of an additive concentrate as described above.

Step 1) is performed according to any known process and is a matter of common practice in the field of fuel supplementation. This step involves defining at least one representative feature of the detergency properties of the fuel composition.

The representative feature of the detergency properties of the fuel will depend on the type of internal combustion engine, for example a diesel or spark ignition engine, the direct or indirect injection system and the location in the engine of the deposits targeted for cleaning and/or maintaining the cleanliness.

For direct-injection diesel engines, the representative feature of the detergency properties of the fuel may correspond, for example, to the power loss due to the formation of deposits in the injectors or restriction of the fuel flow emitted by the injector during the functioning of said engine.

The representative feature of the detergency properties may also correspond to the appearance of lacquering-type deposits on the injector needle (IDID).

Methods for evaluating the detergency properties of fuels have been widely described in the literature and fall within the general knowledge of a person skilled in the art. Nonlimiting examples that will be mentioned include the tests standardized or acknowledged by the profession or the following methods described in the literature:

For direct-injection diesel engines:

the method DW10, standardized engine test method CEC F-98-08, for measuring the power loss of direct-injection diesel engines

the method XUD9, standardized engine test method CEC F-23-1-01 Issue 5, for measuring the restriction of fuel flow emitted by the injector

the method described by the Applicant in patent application WO 2014/029770, pages 17 to 20, for the evaluation of lacquering deposits (IDID), this method being cited by way of example and/or incorporated by reference into the present patent application.

For indirect-injection spark ignition engines:

the Mercedes Benz M102E method, standardized test method CEC F-05-A-93, and

the Mercedes Benz M111 method, standardized test method CEC F-20-A-98.

These methods make it possible to measure the intake valve deposits (IVD), the tests generally being performed on a Eurosuper gasoline corresponding to the standard EN228.

For direct-injection spark ignition engines:

the method described by the Applicant in the article “Evaluating Injector Fouling in Direct Injection Spark Ignition Engines”, Mathieu Arondel, Philippe China, Julien Gueit; Conventional and future energy for automobiles; 10th international colloquium; Jan. 20-22, 2015, pages 375-386 (Technische Akademie Esslingen par Techn. Akad. Esslingen, Ostfildern), for the evaluation of the coking deposits on the injector, this method being cited by way of example and/or incorporated by reference into the present patent application.

the method described in US 2013/0104826 for the evaluation of the coking deposits on the injector, this method being cited by way of example and/or incorporated by reference into the present patent application.

The amount of copolymer (a) and the amount of succinimide compound (b) to be added to the fuel composition to achieve the specification (step 1) described above) will typically be determined by comparison with the fuel composition not specially supplemented with the additive composition according to the invention, the specification given relative to the detergency possibly being, for example, a target power loss value according to the method DW10 or a flow restriction value according to the method XUD9 mentioned above.

The process for maintaining the cleanliness (keep-clean) and/or for cleaning (clean-up) may also comprise an additional step after step 2) of checking the target reached and/or of adjusting the degree of supplementation with the fuel additive composition and/or of adjusting the ratio in which the copolymer (a) and the succinimide compound (b) are present in the fuel additive composition.

According to a particular embodiment, a process for demulsifying or for separating water from a fuel comprises:

1′) the provision of a fuel composition, 2′) the provision of a fuel additive composition as described above, 3′) the introduction of the fuel additive composition into the fuel composition, and 4′) the separation of the fuel and the water.

Preferably, the process for demulsifying the fuel or for separating the water from the fuel comprises, between step 1

and step 2

defined above, a step a

of determining the most suitable supplementation for the fuel, said supplementation corresponding to the selection of the fuel additive composition described above to be incorporated in combination, optionally, with other fuel additives as described previously and determining the degree of treatment necessary to achieve a given specification relative to the demulsifying of the fuel composition.

The selection of the fuel additive composition more particularly corresponds to the selection firstly of one or more copolymers (a) as described above and secondly of one or more succinimide compounds (b) as described previously, but also to the determination of the ratio in which these compounds will be introduced in order to prepare a fuel additive composition according to the invention.

The copolymer(s) (a) and the succinimide compound(s) (b) may be incorporated into the fuel, alone or as a mixture, successively or simultaneously.

Alternatively, the fuel additive composition may be used in the form of a concentrate or of an additive concentrate as described above.

Step a′) is performed according to any known process and is a matter of common practice in the field of fuel supplementation. This step involves defining at least one representative feature of the demulsifying properties of the fuel composition.

The representative feature of the demulsifying properties may correspond, for example, to measurement of the volume of aqueous phase extracted from the fuel according to the standard ASTM D 1094.

Step 3

is also performed according to any process known to those skilled in the art. For example, step 3

may be performed by decantation and separation of the supplemented fuel composition.

The amount of fuel additive composition to be added to the fuel composition to achieve the specification (step a

described above) will typically be determined by comparison with a fuel composition comprising only the copolymer (a) or only the succinimide compound (b).

The amount of copolymer (a) and the amount of succinimide compound (b) to be added to the fuel composition to achieve the specification (steps a

described above) will typically be determined by comparison with a fuel composition comprising only the copolymer (a) or only the succinimide compound (b) present in the fuel additive composition according to the invention, the specification given relative to the demulsifying possibly being, for example, a volume of aqueous phase extracted from the fuel composition according to the standard ASTM D 1094.

The demulsifying process may also comprise an additional step after step 4′) of checking the target reached and/or of adjusting the degree of supplementation with the additive composition and/or of adjusting the ratio in which the copolymer (a) and the succinimide compound (b) are present in the fuel additive composition.

The amount of copolymer (a) and of succinimide compound (b) may also vary as a function of the nature and origin of the fuel, in particular as a function of the content of compounds bearing n-alkyl, isoalkyl or n-alkenyl substituents. Thus, the nature and origin of the fuel may also be a factor to be taken into consideration for step a) and/or for step a

.

The fuel additive composition according to the invention has noteworthy properties as detergent additive in a liquid fuel, in particular in a gas oil or gasoline fuel.

The fuel additive composition according to the invention is also noteworthy in that it makes it possible to obtain fuel compositions which have improved demulsifying properties, when compared with that of fuel compositions comprising only a copolymer (a) or only a succinimide compound (b) as defined above.

The invention is illustrated by the following examples, which are given without any implied limitation.

EXAMPLES 1. Synthesis of a Block Copolymer Starting with 2-ethylhexyl acrylate (EHA) and 2-dimethylaminoethyl acrylate (DMAEA) and Quaternization with 1,2-epoxybutane

The copolymer is obtained by reversible addition-fragmentation chain-transfer (RAFT) radical polymerization according to the following protocol.

A—Materials

Reaction products:

Polymerization initiator: α,α′-azoisobutyronitrile, AIBN (CAS 78-67-1),

RAFT transfer agent: 2-cyano-2-propyl dodecyl trithiocarbonate >97%, CPDTTC (CAS 870196-83-1),

To obtain block A—monomers (m_(a)):

98% 2-ethylhexyl acrylate, EHA (CAS 103-11-7),

To obtain block B—monomers (m_(b)):

98% 2-dimethylaminoethyl acrylate, DMAEA (CAS 2439-35-2)

Quaternizing agent:

99% 1,2-epoxybutane (CAS 106-88-7).

B—Equipment

The various items of equipment used for the characterization of the copolymer are described below.

High Pressure Liquid Chromatography (HPLC):

The chromatograph used is an UltiMate 300 HPLC sold by the company Thermo Fischer.

The stationary phase is a Symmetry Shield RP 18 column.

The mobile phase consists of:

a water/methanol mixture in a 95/5 volume ratio supplemented with methanoic acid CH₂O₂ (CAS 64-18-6) so as to set the pH of the mixture at 5, or

methanol supplemented with methanoic acid so as to set the pH of the mixture at 5. The flow rate of the mobile phase is equal to 1 mL/min. The oven temperature is set at 40° C. The injection volume is 5 μL. The products are detected via a diode array detector.

Nuclear Magnetic Resonance or NMR Spectroscopy:

The ¹H and ¹³C NMR spectroscopy analyses are performed in deuterated chloroform CDCl₃ with a Brüker Avance III 400 MHz spectrometer (¹H Larmor frequency) operating under TopSpin 3.2: SEX 10 mm ¹³C probe with pulsed magnetic field z-gradient and ²H lock operating at 300K and BBI 5 mm ¹H probe with pulsed magnetic field z-gradient and ²H lock operating at 300K. To perform the measurements, an external calibration (1,2,4,5-tetrachloro-3-nitrobenzene or TCNB) is used.

Gel Permeation Chromatography (GPC):

The GPC analyses are performed in THF (tetrahydrofuran) using a Waters Styragel column working at a temperature of 40° C. and at a pressure equal to 645 psi and equipped with an RI (refractive index) detector.

The THF flow rate is equal to 1 mL/min.

In a typical analysis, 100 μL of sample at 0.5% m/m filtered beforehand through a 0.45 μm Millipore filter are injected into the column.

The number-average molar masses (M_(e)) are determined from calibration curves constructed using PMMA (poly(methyl methacrylate)) standards.

C—Copolymerization—Production of an EHA/DMAEA Block Copolymer Step 1—Synthesis of Block A (EHA):

30.0 g (163.0 mmol) of 2-ethylhexyl acrylate (EHA), 0.94 g (2.72 mmol) of 2-cyano-2-propyl dodecyl trithiocarbonate (CPDTTC) and 35 mL of toluene are introduced into a 250 mL round-bottomed flask. 44.3 mg (0.27 mmol) of AIBN are weighed out in a 20 mL round-bottomed flask and then dissolved in 4 mL of toluene. The two solutions are degassed with nitrogen for 30 minutes. The solution containing the EHA monomer is heated to 70° C. When the temperature is reached, the AIBN solution is added to the EHA/CPDTTC mixture using a syringe purged beforehand with nitrogen. The reaction medium is stirred for 24 hours at 70° C. under an inert atmosphere (N₂).

250 μL of the reaction mixture are collected at t₀ (just after the addition of the AIBN) and at t_(f) (after 24 hours of stirring) and are analyzed by HPLC in order to measure the content of residual EHA monomers present in the medium, before and after reaction. The ratio of the areas of the peaks relating to the EHA monomer makes it possible to determine the degree of conversion of the EHA monomers. In the present case, the degree of conversion of the EHA monomers is equal to 98%.

Step 2—Synthesis of Block B (DMAEA):

3.89 g (27.0 mmol) of 2-(dimethylamino)ethyl acrylate (DMAEA) are weighed out in a 50 mL round-bottomed flask. 11 mL of toluene are added. Separately, 44.3 mg (0.27 mmol) of AIBN are weighed out in a 20 mL round-bottomed flask and then dissolved in 3 mL of toluene. The two solutions are degassed with nitrogen for 30 minutes. The DMAEA solution is then added, using a syringe purged beforehand with nitrogen, to the mixture obtained at the end of step 1 and maintained at 70° C. The AIBN solution is finally added to the reaction medium also using a syringe purged beforehand with nitrogen. The reaction medium is stirred for 24 hours at 70° C. under an inert atmosphere (N₂).

250 μL of the reaction mixture are collected at t₀ (just after the addition of the AIBN) and at t_(f) (after 24 hours of stirring) and are analyzed by HPLC in order to measure the content of residual DMAEA monomers present in the medium, before and after reaction. The ratio of the areas of the peaks relating to the DMAEA monomer makes it possible to determine a degree of conversion of the DMAEA monomers equal to 97%.

The contents of residual EHA and DMAEA monomers are determined by ¹H NMR spectroscopy and the relative composition of the copolymer (EHA/DMAEA mole ratio) and the number of EHA and DMAEA units are determined by ¹³C NMR.

For the determination of the contents of residual monomers, the following are detected:

for the residual DMAEA monomers, a main series of signals obtained for chemical shift values equal to 6.43 ppm, 6.15 ppm and 5.82 ppm (AMX system). Assignment of these signals to the DMAEA monomers is confirmed by the observation of two triplets of comparable intensity obtained for chemical shift values equal to 4.3 ppm and 2.7 ppm and associated with the —OCH₂ and —NCH₂ groups of the residual DMAEA monomer,

for the residual EHA monomers, three ethylenic signals of low intensity obtained for chemical shift values equal to 6.39 ppm, 6.13 ppm and 5.80 ppm.

By using the integral of the singlet associated with TCNB (7.7 ppm) as unit reference, and taking into account the molar masses of the compounds involved (184, 143 and 261 g·mol⁻¹ for EHA, DMAEA and TCNB), the content of residual EHA is 0.1% by mass and the content of residual DMAEA is 0.5% by mass.

For the determination of the relative composition (EHA/DMAEA mole ratio), the signal obtained at about 22.8 ppm, assigned to the CH₃CH₂ group of the RAFT end group, is used. By setting its integral at 1, an integral of 0.95 is obtained for the broad signal obtained at 180.6 ppm and associated with the —COON group of the RAFT agent. An integral of 3.35 is also measured for the ¹³C NMR signal of the —C═H group of TCNB. With this same reference, mean integrals are obtained (corrected to take into account of the presence of residual monomers) equal to 62 for EHA and 10 for DMAEA corresponding to the number of units (86/14 EHA/DMAEA mole ratio).

Finally, the number-average molar masses M_(n) and mass-average molar masses M_(w), and also the dispersity index, which reflects the size dispersity Ð Ð=M_(w)/M_(n)), are determined by GPC:

M_(n)=13 800 g/mol; M_(w)=15 900 g/mol; Ð=1.15.

D—Quaternization—Production of an EHA/q-DMAEA Block Copolymer

The following are successively added to the reaction medium obtained at the end of step 2 above:

46 mL of n-butanol,

7.79 g (108 mmol) of 1,2-epoxybutane, and

6.48 g (108 mmol) of acetic acid.

The medium is stirred for 24 hours at 60° C. After returning to room temperature, the solvent is evaporated to dryness.

The EHA/q-DMAEA block copolymer is obtained.

The degree of quaternization of the copolymer obtained is determined by ¹³C NMR. The unresolved peak obtained at about 70 ppm is assigned to the CH₂ of the —CH₂CHOHCH₂CH₃ group located alpha to the quaternized nitrogen atom. On the basis of the EHA/DMAEA molar proportion (86/14) determined above, and by comparing the integral of this unresolved peak to the integral of the characteristic signals of the carbons associated with the EHA units, a degree of quaternization equal to 95% is determined.

2. Preparation of Various Fuel Compositions A—Materials

Additive A1: succinimide compound substituted with a polyisobutyl chain corresponding to formula (XX) defined above in which R₁₁ represents a polyethylenepolyamine chain corresponding to the formula —(CH₂CH₂NH)_(q)—H with q=4. Such a compound is notably described in patent application WO 02/102942.

Additive A2: succinimide compound substituted with a polyisobutyl chain corresponding to formula (XX) defined above in which R₁₁ represents a triazole group corresponding to formula (XXI) and in which R₁₃ is a hydrogen atom. Such a compound is notably described in patent application WO 2015/124584.

B—Compositions

The fuel compositions C₀ to C₅, defined in table 1 below, are prepared by supplementation of a virgin gas oil fuel (GOM B7) corresponding to the standard EN590 containing 7% (vol/vol) or (v/v) of fatty acid methyl esters (FAME).

In table 1 below, the contents are given in ppm by mass relative to the total mass of the fuel compositions obtained.

TABLE 1 Composition C₀ C₁ C₂ C₃ C₄ C₅ Additive A1 — 100 — — 25 — Additive A2 — — 100 — — 25 Copolymer* — — — 100 75 75 *EHA/q-DMAEA block copolymer synthesized above

The composition C₀ corresponds to the virgin fuel not specially supplemented: it constitutes a reference composition.

Compositions C₁ to C₃ are comparative.

Compositions C₄ and C₅ are according to the invention.

3. Evaluation of the Detergent Properties of the Fuel Compositions

The detergency properties of the fuel compositions C₀ and C₃ to C₅ are evaluated according to the XUD9 engine test.

A—XUD9 Engine Test—Determination of the Loss of Flow Rate

The XUD9 test makes it possible to determine the restriction of the flow of a gas oil emitted by the injector of a prechamber diesel engine during its functioning, according to the standardized engine test method CEC F-23-1-01.

The object of this XUD9 test is to evaluate the ability of the gas oil and/or of the additive and/or of the additive composition tested to maintain the cleanliness, “keep-clean” effect, of the injectors of a four-cylinder Peugeot XUD9 A/L prechamber injection diesel engine, in particular to evaluate its ability to limit the formation of deposits on the injectors.

The test is started with a four-cylinder Peugeot XUD9 A/L prechamber injection diesel engine equipped with clean injectors, the flow rate of which was determined beforehand. The engine follows a given test cycle for 10 hours and 3 minutes (repetition of the same cycle 134 times). At the end of the test, the flow rate of the injectors is again evaluated. The amount of fuel required for the test is 60 liters. The loss of flow rate is measured on the four injectors. The results are expressed as a percentage loss of flow rate for various needle lifts. Usually, the fouling values are compared at a needle lift of 0.1 mm since they are more discriminating and more precise and repeatable (repeatability <5%). The change in loss of flow rate before/after test makes it possible to deduce the percentage loss of flow rate. Taking into account the repeatability of the test, a significant detergent effect can be asserted for a reduction in the loss of flow rate, i.e. a gain in flow rate of greater than 10 points (>10%) relative to a virgin fuel.

B—Results

The results obtained are collated in Table 2 below:

TABLE 2 Loss of flow rate* Composition (%) C₀ 70.0% C₃ 1.8% C₄ 11.0% C₅ 31.0% *mean for the four injectors

A loss of flow rate of the injectors equal to 70.0% is observed with the virgin fuel not specially supplemented (fuel composition C₀).

From the results obtained for composition C₃, it is observed that supplementation of the fuel with the copolymer as defined above makes it possible to significantly reduce the loss of flow rate of the engine.

Supplementation of the fuel with the copolymer obtained above thus makes it possible to reduce the amount of deposit formed on the injectors during the functioning of the engine, when compared with the non-supplemented fuel composition (composition C₀).

Introducing into the fuel the combination of the copolymer as defined above with one of the additives A1 or A2 (compositions C₄ and C₅) also makes it possible to significantly reduce the loss of flow rate of the engine.

The combination of the copolymer as defined above with one of the additives A1 or A2 consequently makes it possible to reduce the amount of deposit formed on the injectors during the functioning of the engine, when compared with the fuel that is not specially supplemented (composition C₀).

4. Evaluation of the Demulsifying Properties of the Fuel Compositions

The demulsifying properties of the fuel compositions C₀ to C₅ are also evaluated according to the standard ASTM D 1094.

A—Demulsifying Test (ASTM D 1094)

20 mL of an aqueous buffer solution and 80 mL of fuel composition to be tested are poured into a 100 mL graduated measuring cylinder. The graduated measuring cylinder is then stirred for 2 minutes before being placed on a flat surface. The volume of the aqueous phase located in the lower part of the measuring cylinder is then determined after 3, 5, 7, 10, 15 and 30 minutes simply by reading the volume indicated on the graduated measuring cylinder.

B—Results

The results obtained are collated in Table 3 below:

TABLE 3 Volume of water recovered (in mL) after . . . Composition 3 min 5 min 7 min 10 min 15 min 30 min C₀ 10 18 18 20 20 20 C₁ 0 0 0 0 0 0 C₂ 0 0 0 0 0 2.5 C₃ 0 0 0 ND* 2.5 2.5 C₄ 2.5 2.5 7.5 8.5 10.5 13 C₅ 7 8 10 12 13 15 ND*: volume not determined 18 mL of water are recovered from the fuel composition C₀ after only 5 minutes of rest. After 10 minutes of rest, the entire 20 mL of water initially added to the composition C₀ are recovered.

It is thus observed that the fuel composition not specially supplemented C₀ does not have any demulsifying problems.

After 5 minutes of rest, the volume of water recovered from compositions C₁ to C₃ is zero. Even after 30 minutes of rest, no significant volume of water is recovered from composition C₁. As regards compositions C₂ and C₃, 2.5 mL of water are recovered after 30 minutes and 15 minutes of rest, respectively.

Supplementation of the fuel with a succinimide additive or the copolymer as defined above results in significant degradation of the demulsifying properties of the fuel.

The introduction into an internal combustion engine of such a fuel composition is liable to bring about obstruction of the engine filters or premature corrosion of the engine.

After 5 minutes of rest, 2.5 mL and 8 mL of water, respectively, are recovered from compositions C₄ and C₅ according to the invention.

After 30 minutes of rest, 13 mL and 15 mL of water, respectively, are recovered from compositions C₄ and C₅ according to the invention.

The introduction into the fuel of the combination of the copolymer as defined above and of one of the additives A1 and A2 defined above thus makes it possible to improve the demulsifying properties of the fuel, when compared with the fuel supplemented only with the copolymer or one of the additives A1 and A2.

The additive compositions according to the invention have noteworthy properties as detergent additive in a liquid fuel, in particular in a gas oil fuel.

The additive compositions according to the invention are also noteworthy in that they make it possible to obtain fuel compositions which have improved demulsifying properties, when compared with that of fuel compositions comprising only a copolymer (a) or only a succinimide compound (b) as defined above. 

1. A fuel additive composition comprising: (a) one or more copolymers comprising: at least one unit of formula (I) below:

in which R₁′ is chosen from hydrogen and a methyl group, R′₂ is chosen from C₁ to C₃₄ hydrocarbon-based chains, an aromatic nucleus, and an aralkyl comprising at least one aromatic nucleus and at least one C₁ to C₃₄ alkyl group, and at least one unit of formula (II) below:

in which R₁ is chosen from hydrogen and a methyl group, Z is chosen from an oxygen atom and a group —NR′— with R′ being chosen from a hydrogen atom and C₁ to C₁₂ hydrocarbon-based chains, G comprises a C₁ to C₃₄ hydrocarbon-based chain substituted with at least one quaternary ammonium group and optionally one or more hydroxyl groups, the group G also possibly containing one or more nitrogen and/or oxygen atoms and/or carbonyl groups, (b) at least one compound selected from succinimides substituted with a hydrocarbon-based chain.
 2. The fuel additive composition as claimed in claim 1, in which the group G of formula (II) is represented by one of the formulae (III) and (IV) below:

in which: X⁻ is chosen from hydroxide and halide ions and organic anions, R₂ is chosen from C₁ to C₃₄ hydrocarbon-based chains, optionally substituted with at least one hydroxyl group, it being understood that the group R₂ is connected to Z in formula (II), R₃, R₄ and R₅ are identical or different and chosen independently from C₁ to C₁₈ hydrocarbon-based chains, it being understood that the alkyl groups R₃, R₄ and R₅ may contain one or more groups chosen from: a nitrogen atom, an oxygen atom and a carbonyl group and that the groups R₃, R₄ and R₅ may be connected together in pairs to form one or more rings, R₆ and R₇ are identical or different and chosen independently from C₁ to C₁₈ hydrocarbon-based chains, it being understood that the groups R₆ and R₇ may contain one or more groups chosen from: a nitrogen atom, an oxygen atom and a carbonyl group and that the groups R₆ and R₇ may be connected together to form a ring.
 3. The fuel additive composition as claimed in claim 2, in which the group G of formula (II) is represented by formula (III) in which: X⁻ is chosen from organic anions, R₂ is chosen from C₁ to C₃₄ hydrocarbon-based chains, R₃, R₄ and R₅ are identical or different and chosen independently from C₁ to C₁₈ hydrocarbon-based chains, optionally substituted with at least one hydroxyl group, it being understood that at least one of the groups R₃, R₄ and R₅ contains at least one hydroxyl group.
 4. The fuel additive composition as claimed in claim 1, in which the copolymer(s) (a) consist exclusively of units of formula (I) and of units of formula (II).
 5. The fuel additive composition as claimed in claim 1, in which the copolymer (a) is obtained by copolymerization of at least: one monomer (m_(a)) corresponding to formula (VII) below:

in which R₁′ and R₂′ are as defined in claim 1, one monomer (m_(b)) chosen from those of formula (VIII) below:

in which R₁, Z and G are as defined in claim
 1. 6. The additive composition as claimed in claim 1, in which the copolymer (a) is a block copolymer.
 7. The additive composition as claimed in claim 6, in which the block copolymer comprises at least one block A and at least one block B.
 8. The fuel additive composition as claimed in claim 1, in which the copolymer (a) is a block copolymer, in which the block copolymer comprises at least one block A and at least one block B, and in which the block copolymer comprises: a block A corresponding to formula (XI) below:

in which p is an integer ranging from 2 to 100, R₁′ and R′₂ are as defined in claim 1, a block B corresponding to formula (XII) below:

in which n is an integer ranging from 2 to 40, R₁, Z and G are as defined in claim
 1. 9. The fuel additive composition as claimed in claim 1, in which the succinimide compound substituted with a hydrocarbon-based chain (b) is selected from polyisobutene succinimides.
 10. The fuel additive composition as claimed in claim 1, in which the mass ratio between the copolymer(s) (a) and the succinimide compound (b) ranges from 5:95 to 95:5. 11-19. (canceled)
 20. The fuel additive composition as claimed in claim 1, further comprising an organic liquid, said organic liquid being inert with respect to the copolymer(s) (a) and the succinimide compound (b) and miscible with said fuel.
 21. The fuel additive composition as claimed in claim 20, which comprises from 5 to 99% by mass of copolymer (a).
 22. The fuel additive composition as claimed in claim 20, which comprises from 1 to 95% by mass of organic liquid.
 23. A fuel composition comprising: (1) a fuel derived from one or more sources chosen from the group consisting of mineral, animal, plant and synthetic sources, and (2) a fuel additive composition as defined in claim
 1. 24. The fuel composition as claimed in claim 23, in which the copolymer(s) (a) are present in an amount ranging from 1 to 1000 ppm.
 25. The fuel composition as claimed in claim 23, in which the succinimide compound (b) is present in an amount ranging from 1 to 1000 ppm.
 26. The fuel composition as claimed in claim 23, comprising at least 5 ppm of copolymer(s) (a).
 27. The fuel composition as claimed in claim 23, in which the fuel (1) is chosen from hydrocarbon-based fuels, fuels that are not essentially hydrocarbon-based, and mixtures thereof.
 28. A process for maintaining the cleanliness of and/or for cleaning at least one of the internal parts of an internal combustion engine, wherein said method comprises: the preparation of a fuel composition by supplementation of a fuel with a fuel additive composition as claimed in claim 1 and the introduction of said fuel composition in the internal combustion engine.
 29. The process as claimed in claim 28, wherein said fuel contains water, for improving the separation of the water and the fuel. 